Try rendering your credits as an image sequence.
but this is impossible because I'm rendering it to my 1TB hard drive and I have at least 700 GB left....
Sure it's possible. Many AVI CoDecs are limited to specific maximum file sizes due to how there internal compression math works. Unless you use another format you won't be able to overcome this.
How is your drive formatted (NTFS, FAT32,...)? Some schemes place limits on file size at 4GB.